Shelf life of PCB? Baking time and temperature?
The storage time of PCB, and the temperature and time of using industrial oven to bake PCB are all regulated by the industry.
What is the shelf life of PCB? And how to determine the baking time and temperature?
1. The specification of PCB control
1. PCB unpacking and storage
(1) The PCB board can be directly used online within 2 months of the manufacturing date of the sealed and unopened PCB board
(2) The PCB board manufacturing date is within 2 months, and the unpacking date must be marked after unpacking
(3) PCB board manufacturing date is within 2 months, after unpacking, it must be online and used within 5 days
2. PCB baking
(1) If the PCB is sealed and unpacked for more than 5 days within 2 months of the manufacturing date, please bake at 120±5℃ for 1 hour
(2) If the PCB is more than 2 months from the manufacturing date, please bake it at 120±5℃ for 1 hour before going online
(3) If the PCB is 2-6 months past the manufacturing date, please bake it at 120±5℃ for 2 hours before going online
(4) If the PCB is 6 months to 1 year older than the manufacturing date, please bake at 120±5°C for 4 hours before going online
(5) The baked PCB must be used up within 5 days (put into the IR REFLOW), and the PCB must be baked for another hour before it can be used online.
(6) If the PCB is more than 1 year from the manufacturing date, please bake it at 120±5℃ for 4 hours before going online, and then send it to the PCB factory for re-spraying tin before going online.
3. PCB baking method
(1) Large PCBs (16 PORTs and above, including 16 PORTs) are placed horizontally, with a maximum of 30 pieces in a stack. Open the oven within 10 minutes after the baking is completed, take out the PCB, and lay it flat for natural cooling (need to press the anti-plate bay fixture)
(2) Small and medium-sized PCBs (including 8PORTs below 8PORT) are placed horizontally. The maximum number of a stack is 40 pieces. The number of vertical type is unlimited. Open the oven and take out the PCB within 10 minutes after the baking is completed. Banwan fixture)
2. Preservation and baking of PCBs in different regions
The specific storage time and baking temperature of the PCB are not only related to the production capacity and production process of the PCB manufacturer, but also have a great relationship with the region.
The PCB made by OSP process and pure gold immersion process generally has a shelf life of 6 months after packaging, and it is generally not recommended to bake for OSP process.
The preservation and baking time of PCB has a lot to do with the region. In the south, humidity is generally heavier, especially in Guangdong and Guangxi. In March and April of each year, there will be "returning to the south" weather, and it is rainy every day. Continuously, it was very humid at this time. PCB exposed to the air must be used up within 24 hours, otherwise it is easy to oxidize. After normal opening, it is best to use it up in 8 hours. For some PCBs that need to be baked, the baking time will be longer. In the northern regions, the weather is generally dry, the PCB storage time will be longer, and the baking time can be shorter. The baking temperature is generally 120 ± 5℃, and the baking time is determined according to the specific situation.
For PCB storage time, baking time and temperature, specific problems need to be analyzed in detail, and specific selection needs to be made on the basis of PCB management and control specifications, according to the production capacity, process, region and season of different manufacturers.
Englishen
